1/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * vote.c
5 *
6 * description here
7 *
8 * Copyright (C) 2003, 2004 Oracle.  All rights reserved.
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public
12 * License as published by the Free Software Foundation; either
13 * version 2 of the License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public
21 * License along with this program; if not, write to the
22 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
23 * Boston, MA 021110-1307, USA.
24 */
25
26#include <linux/types.h>
27#include <linux/slab.h>
28#include <linux/highmem.h>
29#include <linux/kthread.h>
30
31#include <cluster/heartbeat.h>
32#include <cluster/nodemanager.h>
33#include <cluster/tcp.h>
34
35#include <dlm/dlmapi.h>
36
37#define MLOG_MASK_PREFIX ML_VOTE
38#include <cluster/masklog.h>
39
40#include "ocfs2.h"
41
42#include "alloc.h"
43#include "dlmglue.h"
44#include "extent_map.h"
45#include "heartbeat.h"
46#include "inode.h"
47#include "journal.h"
48#include "slot_map.h"
49#include "vote.h"
50
51#include "buffer_head_io.h"
52
53#define OCFS2_MESSAGE_TYPE_VOTE     (0x1)
54#define OCFS2_MESSAGE_TYPE_RESPONSE (0x2)
55struct ocfs2_msg_hdr
56{
57	__be32 h_response_id; /* used to lookup message handle on sending
58			    * node. */
59	__be32 h_request;
60	__be64 h_blkno;
61	__be32 h_generation;
62	__be32 h_node_num;    /* node sending this particular message. */
63};
64
65struct ocfs2_vote_msg
66{
67	struct ocfs2_msg_hdr v_hdr;
68	__be32 v_reserved1;
69};
70
71/* Responses are given these values to maintain backwards
72 * compatibility with older ocfs2 versions */
73#define OCFS2_RESPONSE_OK		(0)
74#define OCFS2_RESPONSE_BUSY		(-16)
75#define OCFS2_RESPONSE_BAD_MSG		(-22)
76
77struct ocfs2_response_msg
78{
79	struct ocfs2_msg_hdr r_hdr;
80	__be32 r_response;
81};
82
83struct ocfs2_vote_work {
84	struct list_head   w_list;
85	struct ocfs2_vote_msg w_msg;
86};
87
88enum ocfs2_vote_request {
89	OCFS2_VOTE_REQ_INVALID = 0,
90	OCFS2_VOTE_REQ_MOUNT,
91	OCFS2_VOTE_REQ_UMOUNT,
92	OCFS2_VOTE_REQ_LAST
93};
94
95static inline int ocfs2_is_valid_vote_request(int request)
96{
97	return OCFS2_VOTE_REQ_INVALID < request &&
98		request < OCFS2_VOTE_REQ_LAST;
99}
100
101typedef void (*ocfs2_net_response_callback)(void *priv,
102					    struct ocfs2_response_msg *resp);
103struct ocfs2_net_response_cb {
104	ocfs2_net_response_callback	rc_cb;
105	void				*rc_priv;
106};
107
108struct ocfs2_net_wait_ctxt {
109	struct list_head        n_list;
110	u32                     n_response_id;
111	wait_queue_head_t       n_event;
112	struct ocfs2_node_map   n_node_map;
113	int                     n_response; /* an agreggate response. 0 if
114					     * all nodes are go, < 0 on any
115					     * negative response from any
116					     * node or network error. */
117	struct ocfs2_net_response_cb *n_callback;
118};
119
120static void ocfs2_process_mount_request(struct ocfs2_super *osb,
121					unsigned int node_num)
122{
123	mlog(0, "MOUNT vote from node %u\n", node_num);
124	/* The other node only sends us this message when he has an EX
125	 * on the superblock, so our recovery threads (if having been
126	 * launched) are waiting on it.*/
127	ocfs2_recovery_map_clear(osb, node_num);
128	ocfs2_node_map_set_bit(osb, &osb->mounted_map, node_num);
129
130	/* We clear the umount map here because a node may have been
131	 * previously mounted, safely unmounted but never stopped
132	 * heartbeating - in which case we'd have a stale entry. */
133	ocfs2_node_map_clear_bit(osb, &osb->umount_map, node_num);
134}
135
136static void ocfs2_process_umount_request(struct ocfs2_super *osb,
137					 unsigned int node_num)
138{
139	mlog(0, "UMOUNT vote from node %u\n", node_num);
140	ocfs2_node_map_clear_bit(osb, &osb->mounted_map, node_num);
141	ocfs2_node_map_set_bit(osb, &osb->umount_map, node_num);
142}
143
144static void ocfs2_process_vote(struct ocfs2_super *osb,
145			       struct ocfs2_vote_msg *msg)
146{
147	int net_status, vote_response;
148	unsigned int node_num;
149	u64 blkno;
150	enum ocfs2_vote_request request;
151	struct ocfs2_msg_hdr *hdr = &msg->v_hdr;
152	struct ocfs2_response_msg response;
153
154	/* decode the network mumbo jumbo into local variables. */
155	request = be32_to_cpu(hdr->h_request);
156	blkno = be64_to_cpu(hdr->h_blkno);
157	node_num = be32_to_cpu(hdr->h_node_num);
158
159	mlog(0, "processing vote: request = %u, blkno = %llu, node_num = %u\n",
160	     request, (unsigned long long)blkno, node_num);
161
162	if (!ocfs2_is_valid_vote_request(request)) {
163		mlog(ML_ERROR, "Invalid vote request %d from node %u\n",
164		     request, node_num);
165		vote_response = OCFS2_RESPONSE_BAD_MSG;
166		goto respond;
167	}
168
169	vote_response = OCFS2_RESPONSE_OK;
170
171	switch (request) {
172	case OCFS2_VOTE_REQ_UMOUNT:
173		ocfs2_process_umount_request(osb, node_num);
174		goto respond;
175	case OCFS2_VOTE_REQ_MOUNT:
176		ocfs2_process_mount_request(osb, node_num);
177		goto respond;
178	default:
179		/* avoids a gcc warning */
180		break;
181	}
182
183respond:
184	/* Response struture is small so we just put it on the stack
185	 * and stuff it inline. */
186	memset(&response, 0, sizeof(struct ocfs2_response_msg));
187	response.r_hdr.h_response_id = hdr->h_response_id;
188	response.r_hdr.h_blkno = hdr->h_blkno;
189	response.r_hdr.h_generation = hdr->h_generation;
190	response.r_hdr.h_node_num = cpu_to_be32(osb->node_num);
191	response.r_response = cpu_to_be32(vote_response);
192
193	net_status = o2net_send_message(OCFS2_MESSAGE_TYPE_RESPONSE,
194					osb->net_key,
195					&response,
196					sizeof(struct ocfs2_response_msg),
197					node_num,
198					NULL);
199	/* We still want to error print for ENOPROTOOPT here. The
200	 * sending node shouldn't have unregistered his net handler
201	 * without sending an unmount vote 1st */
202	if (net_status < 0
203	    && net_status != -ETIMEDOUT
204	    && net_status != -ENOTCONN)
205		mlog(ML_ERROR, "message to node %u fails with error %d!\n",
206		     node_num, net_status);
207}
208
209static void ocfs2_vote_thread_do_work(struct ocfs2_super *osb)
210{
211	unsigned long processed;
212	struct ocfs2_lock_res *lockres;
213	struct ocfs2_vote_work *work;
214
215	mlog_entry_void();
216
217	spin_lock(&osb->vote_task_lock);
218	/* grab this early so we know to try again if a state change and
219	 * wake happens part-way through our work  */
220	osb->vote_work_sequence = osb->vote_wake_sequence;
221
222	processed = osb->blocked_lock_count;
223	while (processed) {
224		BUG_ON(list_empty(&osb->blocked_lock_list));
225
226		lockres = list_entry(osb->blocked_lock_list.next,
227				     struct ocfs2_lock_res, l_blocked_list);
228		list_del_init(&lockres->l_blocked_list);
229		osb->blocked_lock_count--;
230		spin_unlock(&osb->vote_task_lock);
231
232		BUG_ON(!processed);
233		processed--;
234
235		ocfs2_process_blocked_lock(osb, lockres);
236
237		spin_lock(&osb->vote_task_lock);
238	}
239
240	while (osb->vote_count) {
241		BUG_ON(list_empty(&osb->vote_list));
242		work = list_entry(osb->vote_list.next,
243				  struct ocfs2_vote_work, w_list);
244		list_del(&work->w_list);
245		osb->vote_count--;
246		spin_unlock(&osb->vote_task_lock);
247
248		ocfs2_process_vote(osb, &work->w_msg);
249		kfree(work);
250
251		spin_lock(&osb->vote_task_lock);
252	}
253	spin_unlock(&osb->vote_task_lock);
254
255	mlog_exit_void();
256}
257
258static int ocfs2_vote_thread_lists_empty(struct ocfs2_super *osb)
259{
260	int empty = 0;
261
262	spin_lock(&osb->vote_task_lock);
263	if (list_empty(&osb->blocked_lock_list) &&
264	    list_empty(&osb->vote_list))
265		empty = 1;
266
267	spin_unlock(&osb->vote_task_lock);
268	return empty;
269}
270
271static int ocfs2_vote_thread_should_wake(struct ocfs2_super *osb)
272{
273	int should_wake = 0;
274
275	spin_lock(&osb->vote_task_lock);
276	if (osb->vote_work_sequence != osb->vote_wake_sequence)
277		should_wake = 1;
278	spin_unlock(&osb->vote_task_lock);
279
280	return should_wake;
281}
282
283int ocfs2_vote_thread(void *arg)
284{
285	int status = 0;
286	struct ocfs2_super *osb = arg;
287
288	/* only quit once we've been asked to stop and there is no more
289	 * work available */
290	while (!(kthread_should_stop() &&
291		 ocfs2_vote_thread_lists_empty(osb))) {
292
293		wait_event_interruptible(osb->vote_event,
294					 ocfs2_vote_thread_should_wake(osb) ||
295					 kthread_should_stop());
296
297		mlog(0, "vote_thread: awoken\n");
298
299		ocfs2_vote_thread_do_work(osb);
300	}
301
302	osb->vote_task = NULL;
303	return status;
304}
305
306static struct ocfs2_net_wait_ctxt *ocfs2_new_net_wait_ctxt(unsigned int response_id)
307{
308	struct ocfs2_net_wait_ctxt *w;
309
310	w = kzalloc(sizeof(*w), GFP_NOFS);
311	if (!w) {
312		mlog_errno(-ENOMEM);
313		goto bail;
314	}
315
316	INIT_LIST_HEAD(&w->n_list);
317	init_waitqueue_head(&w->n_event);
318	ocfs2_node_map_init(&w->n_node_map);
319	w->n_response_id = response_id;
320	w->n_callback = NULL;
321bail:
322	return w;
323}
324
325static unsigned int ocfs2_new_response_id(struct ocfs2_super *osb)
326{
327	unsigned int ret;
328
329	spin_lock(&osb->net_response_lock);
330	ret = ++osb->net_response_ids;
331	spin_unlock(&osb->net_response_lock);
332
333	return ret;
334}
335
336static void ocfs2_dequeue_net_wait_ctxt(struct ocfs2_super *osb,
337					struct ocfs2_net_wait_ctxt *w)
338{
339	spin_lock(&osb->net_response_lock);
340	list_del(&w->n_list);
341	spin_unlock(&osb->net_response_lock);
342}
343
344static void ocfs2_queue_net_wait_ctxt(struct ocfs2_super *osb,
345				      struct ocfs2_net_wait_ctxt *w)
346{
347	spin_lock(&osb->net_response_lock);
348	list_add_tail(&w->n_list,
349		      &osb->net_response_list);
350	spin_unlock(&osb->net_response_lock);
351}
352
353static void __ocfs2_mark_node_responded(struct ocfs2_super *osb,
354					struct ocfs2_net_wait_ctxt *w,
355					int node_num)
356{
357	assert_spin_locked(&osb->net_response_lock);
358
359	ocfs2_node_map_clear_bit(osb, &w->n_node_map, node_num);
360	if (ocfs2_node_map_is_empty(osb, &w->n_node_map))
361		wake_up(&w->n_event);
362}
363
364/* Intended to be called from the node down callback, we fake remove
365 * the node from all our response contexts */
366void ocfs2_remove_node_from_vote_queues(struct ocfs2_super *osb,
367					int node_num)
368{
369	struct list_head *p;
370	struct ocfs2_net_wait_ctxt *w = NULL;
371
372	spin_lock(&osb->net_response_lock);
373
374	list_for_each(p, &osb->net_response_list) {
375		w = list_entry(p, struct ocfs2_net_wait_ctxt, n_list);
376
377		__ocfs2_mark_node_responded(osb, w, node_num);
378	}
379
380	spin_unlock(&osb->net_response_lock);
381}
382
383static int ocfs2_broadcast_vote(struct ocfs2_super *osb,
384				struct ocfs2_vote_msg *request,
385				unsigned int response_id,
386				int *response,
387				struct ocfs2_net_response_cb *callback)
388{
389	int status, i, remote_err;
390	struct ocfs2_net_wait_ctxt *w = NULL;
391	int dequeued = 0;
392
393	mlog_entry_void();
394
395	w = ocfs2_new_net_wait_ctxt(response_id);
396	if (!w) {
397		status = -ENOMEM;
398		mlog_errno(status);
399		goto bail;
400	}
401	w->n_callback = callback;
402
403	/* we're pretty much ready to go at this point, and this fills
404	 * in n_response which we need anyway... */
405	ocfs2_queue_net_wait_ctxt(osb, w);
406
407	i = ocfs2_node_map_iterate(osb, &osb->mounted_map, 0);
408
409	while (i != O2NM_INVALID_NODE_NUM) {
410		if (i != osb->node_num) {
411			mlog(0, "trying to send request to node %i\n", i);
412			ocfs2_node_map_set_bit(osb, &w->n_node_map, i);
413
414			remote_err = 0;
415			status = o2net_send_message(OCFS2_MESSAGE_TYPE_VOTE,
416						    osb->net_key,
417						    request,
418						    sizeof(*request),
419						    i,
420						    &remote_err);
421			if (status == -ETIMEDOUT) {
422				mlog(0, "remote node %d timed out!\n", i);
423				status = -EAGAIN;
424				goto bail;
425			}
426			if (remote_err < 0) {
427				status = remote_err;
428				mlog(0, "remote error %d on node %d!\n",
429				     remote_err, i);
430				mlog_errno(status);
431				goto bail;
432			}
433			if (status < 0) {
434				mlog_errno(status);
435				goto bail;
436			}
437		}
438		i++;
439		i = ocfs2_node_map_iterate(osb, &osb->mounted_map, i);
440		mlog(0, "next is %d, i am %d\n", i, osb->node_num);
441	}
442	mlog(0, "done sending, now waiting on responses...\n");
443
444	wait_event(w->n_event, ocfs2_node_map_is_empty(osb, &w->n_node_map));
445
446	ocfs2_dequeue_net_wait_ctxt(osb, w);
447	dequeued = 1;
448
449	*response = w->n_response;
450	status = 0;
451bail:
452	if (w) {
453		if (!dequeued)
454			ocfs2_dequeue_net_wait_ctxt(osb, w);
455		kfree(w);
456	}
457
458	mlog_exit(status);
459	return status;
460}
461
462static struct ocfs2_vote_msg * ocfs2_new_vote_request(struct ocfs2_super *osb,
463						      u64 blkno,
464						      unsigned int generation,
465						      enum ocfs2_vote_request type)
466{
467	struct ocfs2_vote_msg *request;
468	struct ocfs2_msg_hdr *hdr;
469
470	BUG_ON(!ocfs2_is_valid_vote_request(type));
471
472	request = kzalloc(sizeof(*request), GFP_NOFS);
473	if (!request) {
474		mlog_errno(-ENOMEM);
475	} else {
476		hdr = &request->v_hdr;
477		hdr->h_node_num = cpu_to_be32(osb->node_num);
478		hdr->h_request = cpu_to_be32(type);
479		hdr->h_blkno = cpu_to_be64(blkno);
480		hdr->h_generation = cpu_to_be32(generation);
481	}
482
483	return request;
484}
485
486/* Complete the buildup of a new vote request and process the
487 * broadcast return value. */
488static int ocfs2_do_request_vote(struct ocfs2_super *osb,
489				 struct ocfs2_vote_msg *request,
490				 struct ocfs2_net_response_cb *callback)
491{
492	int status, response = -EBUSY;
493	unsigned int response_id;
494	struct ocfs2_msg_hdr *hdr;
495
496	response_id = ocfs2_new_response_id(osb);
497
498	hdr = &request->v_hdr;
499	hdr->h_response_id = cpu_to_be32(response_id);
500
501	status = ocfs2_broadcast_vote(osb, request, response_id, &response,
502				      callback);
503	if (status < 0) {
504		mlog_errno(status);
505		goto bail;
506	}
507
508	status = response;
509bail:
510
511	return status;
512}
513
514int ocfs2_request_mount_vote(struct ocfs2_super *osb)
515{
516	int status;
517	struct ocfs2_vote_msg *request = NULL;
518
519	request = ocfs2_new_vote_request(osb, 0ULL, 0, OCFS2_VOTE_REQ_MOUNT);
520	if (!request) {
521		status = -ENOMEM;
522		goto bail;
523	}
524
525	status = -EAGAIN;
526	while (status == -EAGAIN) {
527		if (!(osb->s_mount_opt & OCFS2_MOUNT_NOINTR) &&
528		    signal_pending(current)) {
529			status = -ERESTARTSYS;
530			goto bail;
531		}
532
533		if (ocfs2_node_map_is_only(osb, &osb->mounted_map,
534					   osb->node_num)) {
535			status = 0;
536			goto bail;
537		}
538
539		status = ocfs2_do_request_vote(osb, request, NULL);
540	}
541
542bail:
543	kfree(request);
544	return status;
545}
546
547int ocfs2_request_umount_vote(struct ocfs2_super *osb)
548{
549	int status;
550	struct ocfs2_vote_msg *request = NULL;
551
552	request = ocfs2_new_vote_request(osb, 0ULL, 0, OCFS2_VOTE_REQ_UMOUNT);
553	if (!request) {
554		status = -ENOMEM;
555		goto bail;
556	}
557
558	status = -EAGAIN;
559	while (status == -EAGAIN) {
560		/* Do not check signals on this vote... We really want
561		 * this one to go all the way through. */
562
563		if (ocfs2_node_map_is_only(osb, &osb->mounted_map,
564					   osb->node_num)) {
565			status = 0;
566			goto bail;
567		}
568
569		status = ocfs2_do_request_vote(osb, request, NULL);
570	}
571
572bail:
573	kfree(request);
574	return status;
575}
576
577/* TODO: This should eventually be a hash table! */
578static struct ocfs2_net_wait_ctxt * __ocfs2_find_net_wait_ctxt(struct ocfs2_super *osb,
579							       u32 response_id)
580{
581	struct list_head *p;
582	struct ocfs2_net_wait_ctxt *w = NULL;
583
584	list_for_each(p, &osb->net_response_list) {
585		w = list_entry(p, struct ocfs2_net_wait_ctxt, n_list);
586		if (response_id == w->n_response_id)
587			break;
588		w = NULL;
589	}
590
591	return w;
592}
593
594/* Translate response codes into local node errno values */
595static inline int ocfs2_translate_response(int response)
596{
597	int ret;
598
599	switch (response) {
600	case OCFS2_RESPONSE_OK:
601		ret = 0;
602		break;
603
604	case OCFS2_RESPONSE_BUSY:
605		ret = -EBUSY;
606		break;
607
608	default:
609		ret = -EINVAL;
610	}
611
612	return ret;
613}
614
615static int ocfs2_handle_response_message(struct o2net_msg *msg,
616					 u32 len,
617					 void *data, void **ret_data)
618{
619	unsigned int response_id, node_num;
620	int response_status;
621	struct ocfs2_super *osb = data;
622	struct ocfs2_response_msg *resp;
623	struct ocfs2_net_wait_ctxt * w;
624	struct ocfs2_net_response_cb *resp_cb;
625
626	resp = (struct ocfs2_response_msg *) msg->buf;
627
628	response_id = be32_to_cpu(resp->r_hdr.h_response_id);
629	node_num = be32_to_cpu(resp->r_hdr.h_node_num);
630	response_status =
631		ocfs2_translate_response(be32_to_cpu(resp->r_response));
632
633	mlog(0, "received response message:\n");
634	mlog(0, "h_response_id = %u\n", response_id);
635	mlog(0, "h_request = %u\n", be32_to_cpu(resp->r_hdr.h_request));
636	mlog(0, "h_blkno = %llu\n",
637	     (unsigned long long)be64_to_cpu(resp->r_hdr.h_blkno));
638	mlog(0, "h_generation = %u\n", be32_to_cpu(resp->r_hdr.h_generation));
639	mlog(0, "h_node_num = %u\n", node_num);
640	mlog(0, "r_response = %d\n", response_status);
641
642	spin_lock(&osb->net_response_lock);
643	w = __ocfs2_find_net_wait_ctxt(osb, response_id);
644	if (!w) {
645		mlog(0, "request not found!\n");
646		goto bail;
647	}
648	resp_cb = w->n_callback;
649
650	if (response_status && (!w->n_response)) {
651		/* we only really need one negative response so don't
652		 * set it twice. */
653		w->n_response = response_status;
654	}
655
656	if (resp_cb) {
657		spin_unlock(&osb->net_response_lock);
658
659		resp_cb->rc_cb(resp_cb->rc_priv, resp);
660
661		spin_lock(&osb->net_response_lock);
662	}
663
664	__ocfs2_mark_node_responded(osb, w, node_num);
665bail:
666	spin_unlock(&osb->net_response_lock);
667
668	return 0;
669}
670
671static int ocfs2_handle_vote_message(struct o2net_msg *msg,
672				     u32 len,
673				     void *data, void **ret_data)
674{
675	int status;
676	struct ocfs2_super *osb = data;
677	struct ocfs2_vote_work *work;
678
679	work = kmalloc(sizeof(struct ocfs2_vote_work), GFP_NOFS);
680	if (!work) {
681		status = -ENOMEM;
682		mlog_errno(status);
683		goto bail;
684	}
685
686	INIT_LIST_HEAD(&work->w_list);
687	memcpy(&work->w_msg, msg->buf, sizeof(struct ocfs2_vote_msg));
688
689	mlog(0, "scheduling vote request:\n");
690	mlog(0, "h_response_id = %u\n",
691	     be32_to_cpu(work->w_msg.v_hdr.h_response_id));
692	mlog(0, "h_request = %u\n", be32_to_cpu(work->w_msg.v_hdr.h_request));
693	mlog(0, "h_blkno = %llu\n",
694	     (unsigned long long)be64_to_cpu(work->w_msg.v_hdr.h_blkno));
695	mlog(0, "h_generation = %u\n",
696	     be32_to_cpu(work->w_msg.v_hdr.h_generation));
697	mlog(0, "h_node_num = %u\n",
698	     be32_to_cpu(work->w_msg.v_hdr.h_node_num));
699
700	spin_lock(&osb->vote_task_lock);
701	list_add_tail(&work->w_list, &osb->vote_list);
702	osb->vote_count++;
703	spin_unlock(&osb->vote_task_lock);
704
705	ocfs2_kick_vote_thread(osb);
706
707	status = 0;
708bail:
709	return status;
710}
711
712void ocfs2_unregister_net_handlers(struct ocfs2_super *osb)
713{
714	if (!osb->net_key)
715		return;
716
717	o2net_unregister_handler_list(&osb->osb_net_handlers);
718
719	if (!list_empty(&osb->net_response_list))
720		mlog(ML_ERROR, "net response list not empty!\n");
721
722	osb->net_key = 0;
723}
724
725int ocfs2_register_net_handlers(struct ocfs2_super *osb)
726{
727	int status = 0;
728
729	if (ocfs2_mount_local(osb))
730		return 0;
731
732	status = o2net_register_handler(OCFS2_MESSAGE_TYPE_RESPONSE,
733					osb->net_key,
734					sizeof(struct ocfs2_response_msg),
735					ocfs2_handle_response_message,
736					osb, NULL, &osb->osb_net_handlers);
737	if (status) {
738		mlog_errno(status);
739		goto bail;
740	}
741
742	status = o2net_register_handler(OCFS2_MESSAGE_TYPE_VOTE,
743					osb->net_key,
744					sizeof(struct ocfs2_vote_msg),
745					ocfs2_handle_vote_message,
746					osb, NULL, &osb->osb_net_handlers);
747	if (status) {
748		mlog_errno(status);
749		goto bail;
750	}
751bail:
752	if (status < 0)
753		ocfs2_unregister_net_handlers(osb);
754
755	return status;
756}
757